Inelastic Response Spectrum for Seismic Soil Pile Structure Interaction

2016 ◽  
Vol 7 (2) ◽  
pp. 24-34
Author(s):  
Pavan Kumar Emani ◽  
Ritesh Kumar ◽  
Phanikanth Vedula
Keyword(s):  
Interaction Analysis ◽  
Response Spectrum ◽  
Response Spectra ◽  
Response Analysis ◽  
Pile Groups ◽  
Radiation Boundary Condition ◽  
Ground Response Analysis ◽  
Inelastic Response ◽  
Design Spectrum ◽  
Finite Element Software

Structures resting on deep foundations like pile groups are subjected to entirely different kind of vibrations than those resting on shallow foundations, due to the inherent variations in the ground motions experienced at various levels of the foundation. The present work tries to generate response spectrum for single-pile supported structures using inelastic dynamic soil-pile interaction analysis. In the numerical model, the soil nonlinearity includes both separation at soil-pile interface and the plasticity of the near-field soil. The radiation boundary condition is also incorporated in the form of a series of far-field dampers which absorb the out-going waves. Inelastic response spectra for the structure, represented by a SDOF system, is generated after applying the synthetic time histories compatible with design (input) response spectra (as per IS 1893:2002-part I) at the base of pile to investigate the effects of ground response analysis including kinematics and inertial interaction between soil- pile system. It is found that a structure supported by pile foundations should be designed for larger seismic forces/ accelerations than those obtained from the design spectrum given in IS 1893:2002-Part I. The verification of the developed MATLAB program is reported towards the end, using results from commercial Finite Element software ABAQUS.

Study on the Characters of Seismic Response Spectra Based on China Financial Information Mansion

2014 ◽  
Vol 580-583 ◽  
pp. 1729-1733
Author(s):  
Ming Li ◽  
Yuan Qing Wang ◽  
Wei Tao ◽  
Bin Wang ◽  
Qing Xian Yu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Response Spectrum ◽  
Response Spectra ◽  
Financial Information ◽  
Amplification Coefficient ◽  
Response Analysis ◽  
Magnification Factor ◽  
Characteristic Period ◽  
Seismic Coefficient ◽  
Dynamic Magnification Factor

Rare study is done on floor response spectrum of super-high rise building, but it is an important condition for the seismic response analysis of floor subsidiary structure. Therefore, based on the early calculation model of China Financial Information Mansion, the floor response spectrum is calculated under different input ground motion. The floor and ground response spectrum is compared with each other from the seismic coefficient, dynamic amplification coefficient, characteristic period and the form of response spectrum. The results shows that: the floor seismic coefficient and the magnification coefficient are greater or smaller than the ground ones, the biggest difference of which is nearly 1 times; all the floor character period are greater than the ground ones, the biggest difference of which is over 60%; there are obvious differences between the floor and ground dynamic magnification factor spectra form under some conditions, of which the second peak of the former one is probably very large, even near to the peak of the first one, while the latter has no such phenomenon. Therefore, during the process of calculating the seismic response of floor subsidiary structure, it is necessary to consider the change of floor seismic coefficient, dynamic magnification factor, characteristic period and spectra form based on the main structure.

Study on the Ground Response Analysis for Stiff Soil

2014 ◽  
Vol 915-916 ◽  
pp. 122-125
Author(s):  
Xiao Fei Li ◽  
Rui Sun ◽  
Xiao Bo Yu
Keyword(s):  
Seismic Response ◽  
Working Conditions ◽  
Strong Motion ◽  
Response Spectra ◽  
Response Analysis ◽  
Seismic Response Analysis ◽  
Ground Response Analysis ◽  
Ground Acceleration ◽  
Strong Motion Records ◽  
Stiff Soil

In order to test the applicable of the seismic response analysis procedures SHAKE2000 and LSSRLI-1 for class ІІ site, 17 stations and 35 underground strong motion records of KiK-net are selected from Class ІІ site. 210 working conditions are used to verify the applicability of the two soil seismic response analysis programs at Class ІІ site. These two programs are used to calculate the selected working conditions, giving the peak acceleration of the ground, the shear strain and the ground acceleration response spectra. By analyzing the results of the two programs and the measured results to assess the degree of difference between the two methods and which program is closer to the real situation. Studies have shown that in class ІІ site, in most cases, the results of SHAKE2000 and LSSRLI-1 differ little. While comparing with the actual records, SHAKE2000 is closer to the strong motion records.

scholarly journals An Investigation of Local Site Effects Using Linear and Nonlinear analysis and Comparison Between Them

2016 ◽  
Vol 2 (4) ◽  
pp. 113-122 ◽  
Author(s):  
Ali Komak Panah ◽  
Aylin Nouri
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Earthquake Engineering ◽  
Shear Wave Velocity ◽  
Response Spectrum ◽  
Response Analysis ◽  
Site Classification ◽  
Ground Response Analysis ◽  
Soil Response ◽  
Design Response Spectrum

Recent code provisions for building and other structures (1994 and 1997 NEHRP provisions, 1997 UBC) have adopted new site classification. The new site classification system is based on average shear wave velocity to a depth of 30 m. when the shear wave velocity is not available; other soil properties such as undrained shear strength can be used. The study of propagation damages in various earthquakes illustrates the importance of the site effect on the ground seismic characteristics. From the point of the earthquake engineering view, the most important characteristics of the strong ground motion are amplitude, frequency content and duration. All of these properties have a significant effect on earthquake damage. The behavior of soils under cyclic loading is basically nonlinear and hysteretic. Ground response analysis is used to predict the movements of the ground and develop a design response spectrum in order to determine the dynamic stresses and strains and earthquake forces. The profile was studied by using various methods of soil response analysis and finally, the results were examined. In this paper, soil responses were examined by NERA, EERA software and the results compared with each other. Eventually, we concluded that the values obtained from the EERA are more than the value obtained from the NEERA software.

Study on Piping Response Under Multiple Excitation: Part 2 — Validation for Multiple Excitation Analysis of Piping

2013 ◽  
Author(s):  
Satoru Kai ◽  
Tomoyoshi Watakabe ◽  
Naoaki Kaneko ◽  
Kunihiro Tochiki ◽  
Makoto Moriizumi ◽  
...  
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Nuclear Power ◽  
Response Spectrum ◽  
Time History ◽  
Response Spectra ◽  
Shaking Table ◽  
Response Analysis ◽  
Multiple Time ◽  
Floor Response Spectra

The piping in a nuclear power plant is laid across multiple floors of a single building or two buildings, which are supported at many points. As the piping is excited by multiple-inputs from the supporting points during an earthquake, seismic response analysis by multiple excitations is needed to obtain the exact seismic response of the piping. However, few experiments involving such multiple excitation have been performed to verify the validity of multiple excitation analysis. Therefore, analysis of the seismic design of piping in Japan is performed by the enveloped Floor Response Spectrum (FRS), which covers all floor response spectra at all supporting points. The piping response estimated by enveloped FRS is conservative in most cases compared with the actual seismic response by multiple excitations. To perform rational seismic design and evaluation, it is important to investigate the seismic response by multiple excitations and to verify the validity of the analytical method by multiple excitation test. This paper reports the validation results of the multiple-excitation analysis of piping compared with the results of the multiple excitations shaking test using triple uni-axial shaking table and a 3-dimensional piping model (89.1mm diameter and 5.5mm thickness). Three directional moments from the analysis and the shaking test were compared on the validation. As the result, it is confirmed that the analysis by multiple time history excitation corresponds with the test result.

Seismic Ground Response Analysis of Some Typical Sites of Guwahati City

2013 ◽  
Vol 4 (1) ◽  
pp. 83-101 ◽  
Author(s):  
Shiv Shankar Kumar ◽  
A. Murali Krishna
Keyword(s):  
Ground Motion ◽  
Amplitude Ratio ◽  
Response Spectrum ◽  
Strong Motion ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Ground Acceleration ◽  
Surface Level ◽  
Guwahati City

In this study, one dimensional equivalent–linear ground response analyses were performed for some typical sites in the Guwahati city, India. Six bore locations covering about 250 km2 area of the city were considered for the analyses. As the strong motion significantly influences the ground response, seven different recorded ground motions, varying in magnitude (6.1 to 8.1) and other ground motion parameters, were adopted. Seismic site analyses were carried out for all layers of borelogs using all the seven earthquakes. Results are presented in terms of surface acceleration histories, strain and shear stress ratio variation, response spectrum, Fourier amplitude ratio versus frequency. The results indicate that accelerations were amplified the most at the surface level. The range of peak ground acceleration (PGA) values obtained at the ground surface is about 0.2 g to 0.79 for a range of PGA considered at bedrock level (rigid half space at bottom of borelog) of 0.1 g to 0.34 g. The Fourier amplifications of ground motion at surface are in the range of 4.14 – 8.99 for a frequency band of 1.75 Hz to 3.13 Hz. The maximum spectral acceleration at six locations varies in the range of 1.0 g – 4.71 g for all the seven earthquakes. The study clearly demonstrated the role for site effect and the type of ground motion on the ground response. For a given earthquake motion, amplification factors at surface level change by almost about 20% to 70% depending on local site conditions.

scholarly journals A Site-Specific Response Analysis: A Case Study in Hanoi, Vietnam

2020 ◽  
Vol 10 (11) ◽  
pp. 3972 ◽  
Author(s):  
Van-Quang Nguyen ◽  
Muhammad Aaqib ◽  
Duy-Duan Nguyen ◽  
Nguyen-Vu Luat ◽  
Duhee Park
Keyword(s):  
Site Response ◽  
Response Spectra ◽  
Response Analysis ◽  
Specific Response ◽  
Site Class ◽  
Soil Stiffness ◽  
Design Spectrum ◽  
Class D ◽  
The Difference ◽  
A Site

A series of one-dimensional (1-D) site response analyses were performed using the nonlinear (NL) and equivalent linear (EQL) approaches to assess the applicability of the Vietnamese earthquake-resistance design code TCVN 9386: 2012. Six soil profiles were selected from three districts in Hanoi (Vietnam). A number of ground motions compatible with the rock design spectrum were used as input for carrying out analyses. The results highlight that the calculated response is higher than the design spectrum for site class C and lower for site class D. The normalized response spectra of the EQL approach results are higher than those of the NL approach. Moreover, the peak ground accelerations at the surface from EQL analyses are greater than those of the NL method because the latter generates a higher amount of nonlinearity. The results from the NL approach also illustrate that the deamplification phenomenon occurs in the soft soils of the Hanoi region (e.g., soil profile P3 and P5 of site class D). Additionally, the shear strains calculated from the NL method are closely matched with those from the EQL method, the difference between them increasing with a decrease in soil stiffness.

The Uncertainty in Shape Parameter Predictions of Seismic Design Spectra for Nuclear Power Plant

2013 ◽  
Vol 405-408 ◽  
pp. 2025-2029
Author(s):  
Long Jun Xu ◽  
Hong Zhi Zhang
Keyword(s):  
Nuclear Power ◽  
Response Spectrum ◽  
Response Spectra ◽  
Design Spectrum ◽  
Design Spectra ◽  
Motion Data ◽  
Construction Methods ◽  
Normalized Response Spectrum ◽  
Scaling Parameters ◽  
Large Earthquakes

Aiming at the uncertainty of design spectrum raised by the construction methods, a comparative study is conducted in which different methodologies performed calculations of seismic response spectra using the same set of ground motion data from recent large earthquakes. The results of the research allowed some estimates to be made of the scaling method and model uncertainty involved in these calculations. These results were compared with the uncertainty derived from the proposed spectrum of a double-parameter-based bi-normalized response spectrum (DPBNS) approach. It is concluded that the sources of uncertainty that the results reflected are mainly impacted by the spectral type, scaling parameters, as well as imposed fixed conditions adopted in the calculations, for the scaling of the design spectra. Then, a discussion is provided on the limitations of these predications, in particular, of the approaches adopted in the construction of seismic spectra.

Study on the Comparison of Ground Response Analysis for Class І Site

2014 ◽  
Vol 919-921 ◽  
pp. 1031-1034
Author(s):  
Xiao Fei Li ◽  
Rui Sun
Keyword(s):  
Strong Motion ◽  
Response Spectra ◽  
Response Analysis ◽  
Acceleration Response ◽  
Seismic Response Analysis ◽  
Ground Response ◽  
Real Situation ◽  
Ground Response Analysis ◽  
Ground Acceleration ◽  
Maximum Shear Strain

In order to test the applicable of the two equivalent linear seismic response analysis procedures SHAKE2000 and LSSRLI-1 for class І site, 21 underground strong motion records were selected from 11 stations of KiK-net as input earthquake motions. By using these two programs to calculate the peak ground acceleration, soil maximum shear strain and acceleration response spectra. By comparing the results of the two procedures and the measured results to evaluate the proximity of these two methods and then judge which program is closer to the real situation. Studies have shown that in class І site, the results of SHAKE2000 and LSSRLI-1 differ little; but according to the measured records, there are some differences between the two programs results and the measured records. While no matter comparing from which side, SHAKE2000 is closer to the earthquake records.

scholarly journals Effects of Strong Ground Motion with Identical Response Spectra and Different Duration on Pile Support Mechanism and Seismic Resistance of Spherical Gas Holders on Soft Ground

2021 ◽  
Vol 11 (23) ◽  
pp. 11152
Author(s):  
Mio Kobayashi ◽  
Toshihiro Noda ◽  
Kentaro Nakai ◽  
Toshihiro Takaine ◽  
Akira Asaoka
Keyword(s):  
Seismic Response ◽  
Response Spectrum ◽  
Large Earthquake ◽  
Response Spectra ◽  
Response Analysis ◽  
Soft Ground ◽  
Strong Nonlinearity ◽  
Maximum Acceleration ◽  
Support Mechanism ◽  
Strong Ground

Safety measures are required for spherical gas holders to prevent them from malfunctioning even after a large earthquake. In this study, considering the strong nonlinearity of the ground and damage to the pile during an earthquake, a three-dimensional seismic response analysis of the holder–pile–ground interaction system was conducted for an actual gas holder on the soft ground consisting of alternating layers of sand and clay. In the analysis, the seismic response of the structure to strong ground motions of different durations with the same acceleration response spectrum was verified. The results show that the piles were relatively effective in controlling the settlement when the duration of the earthquake motion was long. This is because the axial force acting on the pile increased due to the redistribution of the holder load caused by the lowering of the effective confining pressure of the sand and clay layers during the earthquake, which increased the bearing capacity of the pile. In contrast, when the duration of the seismic motion was short, the piles had little effect on the reduction in the settlement because the maximum acceleration was higher than that in the former case, and the piles immediately lost their support function.

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